The primary objective of this study is to determine whether fetal loss is associated with maternal exposure to pesticides. Both environmental and occupational exposures will be assessed. Secondary objectives include determination of whether pesticide exposures prior to or during pregnancy are most important. The study design will be "case-control", where cases are fetal deaths reported in agricultural counties in the state of California, and controls are an equal number of normal live births in the same counties. The 100 most commonly used pesticides will be examined, plus those pesticides thought to have teratogenic/mutagenic potential that are not in the top 100 list. For several reasons, the state of California offers a unique opportunity for study of the relationship between fetal death and pesticides. First, agriculture is a major industry, with heavy use of pesticides. Second, the state has historical data on pesticide usage by geographical location. This data is specific for small geographical units such as township and section. Third, fetal deaths have been reportable deaths in California since the 1940's, with the certificates of fetal death containing the mother's address, occupation and industry, ethnicity, number of previous miscarriages, and other useful information. Since these records contain the mother's address, they can be linked to the previously mentioned pesticide data to determine which (and in what quantities) pesticides were applied near her residence before and during pregnancy. Questionnaires will be sent to case and control mothers to gather information about occupational pesticide exposures and other risk factors such smoking, alcohol, socioeconomic status, and occupational exposures other than to pesticides. Confounding factors will be accounted for in the analysis of pesticide exposure.